1. Field of the Invention
The invention relates to a high pressure pipe which contains a flexible high pressure hose.
2. Description of the Related Art
High pressure hoses are generally known for the transport of fluid under relatively high pressure. These hoses can for example, be formed by a fabric of nonelastic threads or bundles of threads woven at an angle in relation to the longitudinal direction of the hose, and which can possibly be imbedded in supple plastic. These hoses resist very high pressures, even up to 1000 kg/cm.sup.2, but are, even when they are filled with fluid under pressure, very flexible and supple.
This flexibility can in certain applications be an advantage but for other applications is unacceptable. The latter situation is, for example, the case where the high pressure pipe connects to a spray nozzle for making a hole in the ground and at least where the spray nozzle has to be pushed forward into the ground by the high pressure hose. By pushing the nozzle with with the supple high pressure hose, this hose is going to bend or buckle. If the hose is unwound from a drum, it can be flattened at the location of the guides which direct the hose when pushing it into the ground. It is for that reason that in the above mentioned applications situation, use is not made of high pressure hoses but of relatively stiff pipes which, for example, are made of metal. Ordinary metal pipes are however not resistant to very high pressures. Therefore high pressure pipes must be made from special alloys, which are relatively expensive, or of cheaper material, such as steel, which must then, however, be produced very thick in order to withstand the high pressure, and are therefore also relatively expensive. In the last case, where thick stiff pipes are used these pipes are totally untransformable, and it is therefore impossible to wind them up onto or unwind them from a drum, such as for example with the procedure and device for making a hole in the ground according to Belgian patent no. 905 265.